A few years ago, I was at my vet’s office when an older couple brought in a Chihuahua pup who was very ill. Despite the staff’s best efforts, less than an hour later the pup was dead. The cause? A drug overdose, due to a prescription error made by a human pharmacy.

The prescribed amount for this tiny pup was 0.4 mg, but the pharmacist, who had probably never come across such a small dosage, had misread the prescription as 4 mg, so the pup had received 10 times as much of the drug as he was supposed to get. My vet accepted partial responsibility, as he had failed to write a zero in front of “.4” on the prescription. (Veterinarianss are now being encouraged to use leading, but not trailing, zeroes when they write prescriptions to help avoid such mistakes.)

It had never occurred to me before that day to review a prescription for accuracy, but you’d better believe I’m careful to check them now. Errors are less likely to occur with prescription filled at your vet’s office, since the people filling the prescription know their patients and are familiar with common dosages for dogs. The growing use of human pharmacies filling prescriptions for our dogs, however, means we must also deal with pharmacists who may know little or nothing about a canine patient’s needs, or have any idea of the size of the patient when filling the prescription. This ignorance can lead to serious, even fatal, errors.

Potential for mistakes

Incorrect dosage amounts are not the only mistakes that human pharmacists may make when filling prescriptions written for pets. Pharmacists currently receive no training in the use of drugs for non-human patients. The VIN (Veterinary Information Network) News Service has written about several problems that veterinarians have seen in recent years.

One example was a pharmacist who told a client that the dosage of diazepam (Valium) that her vet had prescribed for her dog could kill him. The pharmacist was unaware that dosages of many medications, including those used to treat hypothyroidism, seizures, and anxiety, are much higher for dogs than they are for humans, due to differences in metabolism and other factors.

The prescribed dosage was correct, but the client was now afraid to give the medication to her dog, who suffered as a result. The dog was recovering from knee surgery and the medication had been prescribed to help keep him off his leg and reduce his anxiety. Without it, he overused and injured the leg, requiring additional surgery.

One of the first cases to result in a formal complaint followed by regulatory action, the state’s Pharmacy Board issued a “notice of correction” to the pharmacist. In response, he asked that the drug store chain for which he worked provide its pharmacies with references in veterinary dosing and indications, which has since been done.

In other cases, pharmacists have altered doses, believing they are correcting a veterinarian’s mistake, or substituted medications inappropriately, without notifying either the veterinarian or the client of the changes. This has led to serious problems for some dogs. For example, when a pharmacist substitutes a different type of insulin for what a diabetic dog is accustomed to, this can cause changes in glucose control and even life-threatening hypoglycemia. In other examples, medication doses have been lowered to the point that they are no longer effective, leading to suffering and even death in some dogs. In one case, a client reduced her dog’s seizure medication on the advice of a pharmacist, and the dog developed intractable seizures that led to euthanasia.

Most of the time, veterinarians are unaware of the changes, or learn about them long after the fact, making it difficult for them to treat their patients effectively, or to report what happened to the appropriate authorities.

These problems are not new, but they are increasing as more people turn to human pharmacies in order to save money on their pets’ prescriptions. Mistakes may also occur more frequently with large national chains that fill high volumes of prescriptions, where a pharmacist is unlikely to develop a personal relationship with either veterinarians or clients. Pending congressional legislation that would require veterinarians to provide all prescriptions in writing to pet owners with a notice that they can fill the prescription elsewhere could contribute to even more frequent problems in the future.

Take-home message

Whenever your vet gives you a prescription, make sure you understand the prescribed amount and dosing schedule. Then check the label to make sure that the name of the medication is the same as what your vet prescribed, and that the printed instructions match what your vet told you to give. If you have any questions about the medication, check with your vet, rather than relying on information from the pharmacist. If a pharmacy offers you a substitute medication, do not accept it until and unless you confirm with your vet that the substitution is acceptable. And never change your dog’s medication based on a pharmacist’s advice.

When Buying Veterinary Drugs Online, Look for Accredited Sites

Purchasing veterinary medications such as heartworm preventatives online can offer significant cost savings, but how can you be sure that you’re buying the real thing and not counterfeit products from China, which can be impossible to tell apart?

I recently read about a dog who tested positive for heartworms despite being given monthly preventative medications. The reason may be that the heartworm preventative the owner purchased online was not what it claimed to be.

The Veterinary Information Network (VIN) looked into Nuheart, a generic form of ivermectin that claims to be comparable to Heartgard. It is sold over the counter in Australia, where no prescription is required. VIN reported that one online pet pharmacy marketing Nuheart in the U.S. lists a street address in Washington state that belongs to Mail Boxes Plus. That same address is linked to a number of other online pharmacies whose websites are registered to entities that share an address in the South Pacific Cook Islands. None of those companies responded to VIN’s attempts to contact them by phone or email.

This is just one example of a widespread problem with drugs being sold on the Internet that may be counterfeit, adulterated, or expired. Warnings abound regarding the dangers of buying medications online. The U.S. Food and Drug Administration (FDA) states that it “has found companies that sell unapproved pet drugs and counterfeit pet products, make fraudulent claims, dispense prescription drugs without requiring a prescription, and sell expired drugs.”

So how can you be sure that “what you see is what you get”? One solution is to look for the Veterinary-Verified Internet Pharmacy Practice Sites (Vet-VIPPS) seal of approval from the National Association of Boards of Pharmacy (NABP).

When Vet-VIPPS was first announced in 2009, it sounded like a great idea. Unfortunately, no veterinary pharmacies were approved at that time, but the situation has improved. A quick search yielded 11 verified online veterinary pharmacy sites. I was pleased to see four sites I’ve recommended on the list: 1-800-PetMeds, Drs. Foster & Smith, andPetCareRx.

Note these pharmacies will not offer to sell you prescription medications without a prescription. Administering medication without the help of a veterinarian is not a smart way to save money. Mistakes can range from giving the wrong dosage to using the wrong medication entirely, or giving dangerous combinations of drugs. Some inappropriate medications are only ineffective; others could be dangerous or even fatal.

The FDA has the following suggestions for protecting yourself when purchasing pet medications online, using the acronym AWARE:

Ask your veterinarian if they know anything about the site you plan to use.

Watch for red flags, such as not requiring a prescription, not listing an address and phone number, or not having a pharmacist available to answer questions.

Use common sense when purchasing medications online; if a deal seems too good to be true, you’re likely not getting the real thing.

Another consideration when buying medications online is that the manufacturer’s warranty may be invalidated by an online purchase. Manufacturers of heartworm preventatives in particular guarantee products only when purchased from a veterinarian; not even a VIPPS-accredited pharmacy will do.

Fortunately, some online pharmacies offer their own guarantees. 1-800-PetMeds, for example, claims that its guarantee is even better than the manufacturer’s: it will cover the cost of treatment if your dog becomes infected while taking any heartworm product purchased from its site as long as the drug has been used for nine consecutive months prior to diagnosis (see 1800petmeds.com/guarantee.jsp). Drs. Foster & Smith also offers its own guarantee for all heartworm preventatives it sells (drsfostersmith.com/general.cfm?gid=569).

Many pets need to take drugs that have been compounded, where the drug’s dosage, form, or flavor are manipulated to make them work for animals. Compounding pharmacies produce drugs in dosages suitable for small dogs, in flavors that pets are willing to eagerly eat, and in forms such as transdermal, where the drug is applied to the skin rather than given orally. They can sometimes be a source for drugs that have been discontinued as well. Because of their specialized nature, compounded drugs don’t go through a drug-approval process with the FDA, and so are not formally tested for safety or efficacy.

Compounded drugs can be life-savers for some pets, but they can be ineffective if poor-quality ingredients are used, and dangerous when mistakes are made. In 2009, 21 polo horses died after being injected with a vitamin compound that included a toxic amount of selenium due to an error by the compounding pharmacy that made it.

The NABP doesn’t list any compounding pharmacies, although Choice Compounding Pharmacy (choicecompoundingpharmacy.com) was recently granted approval. In addition, there’s a separate organization, the Pharmacy Compounding Accreditation Board (PCAB) that focuses on this area of specialization. The PCAB was created in 2004 in an attempt by the pharmacy industry to police itself and raise the quality of compounded drugs. Go to its web site at pcab.info to search for accredited compounding pharmacies by state.

Not every pharmacy without approval from VIPPS or PCAB sells counterfeit or dangerous products. The approval process is costly and takes time; not all pharmacies can afford it. In the absence of reliable information, however, these accreditations offer peace of mind when buying veterinary medications for your dog from someone other than your veterinarian.